You might try taking a Skimboard and/or Boogie board and hide your twintip in the same bag, that is if it can fit (you're allowed up to two boards per bag as long as it's under 50lbs). According to HIA's sight, these type of boards are considered "sand boards" and are treated as checked baggage which are subject to the regular priced fees.

If it were me I would just use FedEx or LugLess.It's not much cheaper, but is priceless for the hassle is saves you.